[Boatanchors] [Glowbugs] Heater choke

J. Forster jfor at quik.com
Tue Mar 8 22:52:47 EST 2011

The bifilar filament choke is common in WW II mil gear, from HF through
UHF at least.



> From: Ian Wilson [mailto:ianmwilson73 at gmail.com]
> Grounded-grid amplifiers using directly heated tubes?
> Possibly.  I remember it being like the single layer RF chokes wound with
> DCC enameled wire on a ceramic (or something) form maybe 1/2” in diameter
> only with two windings running in parallel, one to each side of the
> heater.
> I can see where this would be good for a grounded grid amp but each side
> of
> the heater was bypassed to ground for RF and the winding supplying it was
> center tapped with the tap grounded or keyed.  This is why I’m thinking it
> was pre-GG and the response about the Eimac tubes comes close.
> OTOH, it may have been a GG amp and I’m confusing the bypass caps with
> another amp.  As we all know, I am very good at getting confused.  :-)
> But
> the choke itself sticks most firmly in my mind as something I wanted to
> use
> in a 1920s or 1930s Tx.
> At least one of the articles on the
> Glowbugs site (may be "Egad! A 9-Tube Amplifier") talks about this (sorry
> don't have time
> to find the link right now).
> Nine tubes?  Little bitty ones run in parallel to make one big one?  :-D
> Best regards,
> Michael, WH7HG BL01xh WPE3ARS, ex-KN3MXO, ex-K3MXO A&P PP BGI LS/MFT
> Whirled Infamous Author and all around really strange person
> http://www.nationalmssociety.org/chapters/NTH/index.aspx
> http://wh7hg.blogspot.com/
> http://kludges-other-blog.blogspot.com
> <http://kludges-other-blog.blogspot.com/>
> Hiki Nô!
> _______________________________________________
> Boatanchors mailing list
> Boatanchors at puck.nether.net
> https://puck.nether.net/mailman/listinfo/boatanchors

More information about the Boatanchors mailing list